{"title":"New results on third-order coding rate for universal fixed-to-variable source coding","authors":"O. Kosut, L. Sankar","doi":"10.1109/ISIT.2014.6875322","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875322","url":null,"abstract":"Converse and achievable results on the third-order coding rate for universal fixed-to-variable source coding are presented. The authors previously introduced a new universal non-prefix Type Size code for memoryless sources in which codewords lengths are chosen in ascending order of type class sizes. This paper presents a converse on the third-order coding rate for general class of fixed-to-variable codes and proves the optimality of Type Size codes for memoryless sources. The third-order coding rate for a two-stage code is also developed and is shown to be strictly larger than achieved by the Type Size code.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133008185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A robust R-FFAST framework for computing a k-sparse n-length DFT in O(k log n) sample complexity using sparse-graph codes","authors":"S. Pawar, K. Ramchandran","doi":"10.1109/ISIT.2014.6875154","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875154","url":null,"abstract":"The Fast Fourier Transform (FFT) is the most efficiently known way to compute the Discrete Fourier Transform (DFT) of an arbitrary n-length signal, and has a computational complexity of O(n log n). If the DFT X⃗ of the signal x⃗ has only k non-zero coefficients (where k <; n), can we do better? In [1], we presented a novel FFAST (Fast Fourier Aliasing-based Sparse Transform) algorithm that cleverly induces sparse graph codes in the DFT domain, via a Chinese-Remainder-Theorem (CRT)-guided sub-sampling operation of the time-domain samples. The resulting sparse graph code is then exploited to devise a simple and fast iterative onion-peeling style decoder that computes an n length DFT of a signal using only O(k) time-domain samples and O(k log k) computations, in the absence of any noise. In this paper, we extend the FFAST framework of [1] to the case where the time-domain samples are corrupted by white Gaussian noise. In particular, we show that the extended noise robust algorithm R-FFAST computes an n-length k-sparse DFT X⃗ using O(k log n)1 noise-corrupted time-domain samples, in O(n log n) computations2. While our theoretical results are for signals with a uniformly random support of the non-zero DFT coefficients and additive white Gaussian noise, we provide simulation results which demonstrates that the R-FFAST algorithm performs well even for signals like MR images, that have an approximately sparse Fourier spectrum with a non-uniform support for the dominant DFT coefficients.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122246044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On storage codes allowing partially collaborative repairs","authors":"Shiqiu Liu, F. Oggier","doi":"10.1109/ISIT.2014.6875272","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875272","url":null,"abstract":"We consider the design of codes for distributed storage systems that are amenable to repair. We introduce the notion of partial collaboration to capture the property that nodes participating in a repair process may collaborate to different extents, bringing more nuances to the known cases: no collaboration or full collaboration during repair. We compute for this scenario the storage (per node) when the repair bandwidth (per node) is minimal, and conversely the repair bandwidth when the storage is minimal. We provide a generic code construction that enables repair of several failures through partial collaboration.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120944957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Weakly secure data exchange with Generalized Reed Solomon codes","authors":"M. Yan, A. Sprintson, I. Zelenko","doi":"10.1109/ISIT.2014.6875056","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875056","url":null,"abstract":"We focus on secure data exchange among a group of wireless clients. The clients exchange data by broadcasting linear combinations of packets over a lossless channel. The data exchange is performed in the presence of an eavesdropper who has access to the channel and can obtain all transmitted data. Our goal is to develop a weakly secure coding scheme that prevents the eavesdropper from being able to decode any of the original packets held by the clients. We present a randomized algorithm based on Generalized Reed-Solomon (GRS) codes. The algorithm has two key advantages over the previous solutions: it operates over a small (polynomial-size) finite field and provides a way to verify that constructed code is feasible. In contrast, the previous approaches require exponential field size and do not provide an efficient (polynomial-time) algorithm to verify the secrecy properties of the constructed code. We formulate an algebraic-geometric conjecture that implies the correctness of our algorithm and prove its validity for special cases. Our simulation results indicate that the algorithm is efficient in practical settings.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121118419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Variable-density sampling on the dual lattice","authors":"Peng Zhang, Sumei Sun, Cong Ling","doi":"10.1109/ISIT.2014.6875044","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875044","url":null,"abstract":"Sampling from certain probability distribution shows better recovery performance than uniform sampling in literature. However, a comprehensive theoretical analysis concerning more realistic signal models is still lacking. In this paper, we consider the sampling of stochastic processes and random fields in the Fourier domain. We propose a new variable-density sampling and linear reconstruction technique, and prove its theoretical recovery guarantee. For high dimensional random fields, uniform sampling requires a number of samples increasing exponentially with the dimension, while the variable density sampling scheme guarantees faithful recovery performance with a polynomial size of random samples.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116617069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cache-induced opportunistic MIMO cooperation: A new paradigm for future wireless content access networks","authors":"An Liu, V. Lau","doi":"10.1109/ISIT.2014.6874792","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6874792","url":null,"abstract":"Advanced interference mitigation techniques such as cooperative MIMO (CoMP) have been proposed to improve the spectral efficiency of future 5G wireless networks. However, conventional CoMP is quite costly because it requires high capacity backhaul for payload exchange between the BSs. In this paper, we propose a novel solution framework of cache-induced opportunistic CoMP to achieve the CoMP gain for multimedia streaming applications without expensive backhaul. Specifically, by caching a portion of the media files, the base stations (BS) opportunistically employ CoMP to transform the cross-link interference into spatial multiplexing gain. We study a mixed-timescale optimization of (short timescale) MIMO precoding and (long timescale) cache control to minimize the transmit power under the QoS constraint. By exploiting the timescale separations of the optimization variables, we derive low complexity multi-timescale solution for the MIMO precoding and cache control. The solution has significant gains over various baselines.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115033408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Codes for high performance write and read processes in multi-level NVMs","authors":"Evyatar Hemo, Yuval Cassuto","doi":"10.1109/ISIT.2014.6875202","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875202","url":null,"abstract":"Multi-level memory cells are used in non-volatile memories in order to increase the storage density. Using multi-level cells, however, imposes higher read and write latencies limiting high speed applications. In this work we study the tradeoff between storage density and write/read performance using codes. The contributions are codes that give high-performance write and read processes with minimal reduction in storage density. We describe the codes, give an analytical treatment of their information rate and speed, and compare them with more basic access schemes and upper bounds.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116184067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A greedy search algorithm with tree pruning for sparse signal recovery","authors":"Jaeseok Lee, Seokbeop Kwon, B. Shim","doi":"10.1109/ISIT.2014.6875153","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875153","url":null,"abstract":"In this paper, we propose a new sparse recovery algorithm referred to as the matching pursuit with a tree pruning (TMP) that performs efficient combinatoric search with the aid of greedy tree pruning. Two key ingredients of the TMP algorithm are pre-selection to put a restriction on the indices of columns in Φ being investigated and tree pruning to avoid the investigation of unpromising paths in the search. In the noisy setting, we show that TMP identifies the support (index set of nonzero elements) accurately when the signal power is larger than the constant multiple of noise power. In the empirical simulations, we confirm this results by showing that TMP performs close to an ideal estimator (often called Oracle estimate) for high signal-to-noise ratio (SNR) regime.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117023522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Distributed decode-forward for multicast","authors":"S. Lim, Kwang Taik Kim, Young-Han Kim","doi":"10.1109/ISIT.2014.6874910","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6874910","url":null,"abstract":"A new coding scheme for multicasting a message over a general relay network is presented that extends both network coding for graphical networks by Ahlswede, Cai, Li, and Yeung, and partial decode-forward for relay channels by Cover and El Gamal. For the N-node Gaussian multicast network, the scheme achieves within 0.5N bits from the capacity, improving upon the best known capacity gap results. The key idea is to use multicoding at the source as in Marton coding for broadcast channels. Instead of recovering a specific part of the message as in the original partial decode-forward scheme, a relay in the proposed distributed decode-forward scheme recovers an auxiliary index that implicitly carries some information about the message and forwards it in block Markov coding. This scheme can be adapted to broadcasting multiple messages over a general relay network, extending and refining a recent result by Kannan, Raja, and Viswanath.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115499853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tobias Sutter, Peyman Mohajerin Esfahani, David Sutter, J. Lygeros
{"title":"Capacity approximation of memoryless channels with countable output alphabets","authors":"Tobias Sutter, Peyman Mohajerin Esfahani, David Sutter, J. Lygeros","doi":"10.1109/ISIT.2014.6875366","DOIUrl":"https://doi.org/10.1109/ISIT.2014.6875366","url":null,"abstract":"We present a new algorithm, based on duality of convex programming and the specific structure of the channel capacity problem, to iteratively construct upper and lower bounds for the capacity of memoryless channels having continuous input and countable output alphabets. Under a mild assumption on the decay rate of the channel's tail, explicit bounds for the approximation error are provided. We demonstrate the applicability of our result on the discrete-time Poisson channel having a peak-power input constraint.","PeriodicalId":127191,"journal":{"name":"2014 IEEE International Symposium on Information Theory","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121284511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}